We went over this before.  *I* consider the 2.x behavior a mistake, and
a decision was made to change in 3.0.  It got much worse in 3.0 because
all literals are Unicode (except byte literals).

To add a unicode value to a raw string, just concatenate a raw string
and a non-raw string, e.g.

r'whatever' '\u1234' r'whatever'

I don't understand what you meant by '\x1234' -- the \x escape only
accepts 2 hex digits.